For risk assessment purposes it is important to establish the relations between the applied or exposure dose and tissue specific concentrations and the relationship of this dose to toxicological or carcinogenic outcomes. It is therefore necessary to analyze tissue specific concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and other related chlorinated dibenzo-p-dioxins and furans in treated animals. We are therefore establishing a contract for analysis of TCDD and other related compounds in animal tissues. We will require high resolution gas chromatography/mass spectroscopy to quantitate these chemicals in these samples.